In a modern music landscape where genre is pretty much nonexistent, the lines are becoming even further blurred. That's why music lovers barely flinched when news broke that Justin Bieber will work with Kanye West and his "homey" Drake on his next album.

However, more than a decade ago, major mainstream artists like Britney Spears or even *NSYNC (whose very own Justin Timberlake later went on to work with hip-hoppers) would never have thought about hooking up with rappers like Eminem, for instance. In fact, they were the punch line to many of Em's finest rhymes during the "TRL" era.

Today, pop stars and rap stars are unapologetically sharing their love for one another. Lil Wayne, who recently worked with artists including Joe Jonas and Jennifer Lopez, seems to be one of the guys leading the charge. In addition to appearing on tracks with pop stars, Demi Lovato's and Bieber's covers of his track "How to Love" have made headlines. So, what is it about Weezy?

"I just loved the way that Lil Wayne took a risk doing the song 'How to Love,' " Lovato explained. "And when I really listened to it, it's such a great song."

That enthusiasm for his work, according to Vibe Music Editor John Kennedy, has a lot to do with Weezy "the man" as well as Weezy "the artist." "Wayne appeals to the pop world because he's obviously got a tremendous following and is a talented artist, but he's a character outside of the music. His image off-wax is just as prominent as his rhymes on record," he explained. "So when you get Wayne on a record, it's more than just a hot 16, you're getting a rebel to society: the sagging denims, tats all over, diamond grills. It just adds rock star flavor with hip-hop appeal."

"On an artistic level, he just seems like an exciting guy to be around who is also willing to try just about everything, so I imagine pop stars can basically say, 'Hey, can you do this weird thing?' and he'd say yes," Entertainment Weekly staff writer Kyle Anderson added about Wayne's appeal. "From a more business standpoint, working with Wayne not only means chart and radio recognition but also instant cool. He has a cachet that hasn't faded yet."

But Wayne is hardly the only guy in the game defying the laws of hip-hop and pop. Country superstar Taylor Swift has certainly done her part, appearing in concert with guys like T.I. and B.o.B. "I'm a huge hip-hop fan, and it's been so amazing to have so many incredible artists come out and to get to sing the hooks on their songs that I've been blasting in my car for the last couple years," she explained. "It's been awesome. I couldn't have asked for more amazing special guests on this tour, and we're not finished yet."

But it's not just the pop stars singing the praises of rappers and hoping to get some street cred. Rappers are clamoring to hook up with their pop counterparts too, picking up where artists like Mariah Carey/O.D.B. and Christina Aguilera/Redman left off. And recently, Aguilera's former pop rival, Spears, jumped on the trend when she toured with Nicki Minaj.

When MTV News caught up with Minaj backstage on the Femme Fatale Tour, she said that the crossover success has been intriguing and surprising. "I'm always surprised," she said. "I don't really expect them to know all the records, but I guess it just kind of transcends all genres of music at this point."

As the genre-bending continues, it seems that the pairings are likely to get more and more unexpected. "I met Justin [Bieber] back in February. He's a cool kid and sh--," Tyler, the Creator said of his desire to work with the teen star. "When I got in there, he was talkin' about the 'Yonkers' video and sh--. It was weird, because I was sitting here starstruck, like, 'Oh, f---, it's Bieber. He's asking me questions.' I'm like, 'Shut the f--- up so I can talk to you.' "

What do you think of the pop/ hip-hop crossover? Tell us in the comments.